Hydro-metallurgical mining has been developed over the past twenty years with large scale application. The first success was in recovery of uranium and other rare elements under work by the Atomic Energy Commission.
General Mills Chemicals, Inc., Minneapolis, Minnesota has developed a series of ion exchange reagents for particular metals and marketed the compounds under the trademark LIX. These developments raise the expectations of developing a chemical extractant for any metal.
One of the more visible of the commercially successful LIX organic liquids has been that used in the mining of copper. A relatively weak acid has comprised an extractor loop which chemically dissolves copper from a dump, or sump, of ore. The LIX ion exchange compound, carried in an organic solvent such as kerosene, is mixed with the copper-pregnant acid. The hydrogen ion of the compound exchanges for the copper of the acid. After separation from its copper, the weak acid is returned to the ore of the dump. The ion exchange compound, loaded with the copper, is mixed with an acid strong enough for its hydrogen ions to push the copper from the loaded ion exchange compound and regenerate the compound with the hydrogen ions. From another viewpoint, the ion exchange compound in its reaction with the acid streams, shifts its equilibrium in accordance with the amount of hydrogen ions available from the acid streams.
The present problem of mixing and separation is not limited to the ion exchange systems. In any system where two immiscible fluids require thorough mixing for a physical or chemical exchange between the fluids there follows the problem of separation of the fluids. If two immiscible fluids exchange a third fluid between them, dependent upon the solubility of the third fluid in the first two fluids, there is a mixing and separation problem to be solved.
However, for disclosing the present invention, the embodiment will relate to an ion exchange system which may also be termed a solvent extraction system. The terminology of the disclosure may become fairly specific, but the problem solved is a common denominator of a broad range of liquid-liquid exchange systems.